α-glycosyl-L-ascorbic acid, and it's preparation and uses

Abstract

α-Glycosyl-L-ascorbic acid exhibiting no direct reducing activity is formed in a solution containing L-ascorbic acid and an α-glucosyl saccharide when subjected to the action of a saccharide-transferring enzyme. α-Glycosyl-L-ascorbic acid is superiorly stable, and readily hydrolyzable in vivo to exhibit the activities inherent to L-ascorbic acid. Thus, α-glycosyl-L-ascorbic acid is favorably useful as a stabilizer, quality-improving agent, antioxidant, physiologically active agent and uv-absorbent in food pharmaceutical and cosmetic industries.

We claim: 
     
       1. In a composition of matter comprising a foodstuff or a cosmetic, the improvement wherein said composition of matter further comprises an α-glycosyl-L-ascorbic acid of the formula: ##STR5## wherein n is an integer of 0 to 6, said ascorbic acid exhibiting no direct reducing activity. 
     
     
       2. A foodstuff which contains an α-glycosyl-L-ascorbic acid exhibiting no direct reducing activity. 
     
     
       3. The foodstuff of claim 2, wherein the content of said α-glycosyl-L-ascorbic acid is at least 0.001 w/w %. 
     
     
       4. The foodstuff of claim 3, wherein said α-glycosyl-L-ascorbic acid is 2-O-α-D-glucosyl-L-ascorbic acid. 
     
     
       5. The foodstuff of claim 3, wherein said α-glycosyl-L-ascorbic acid is prepared by providing a solution which contains at least 1 w/v % L-ascorbic acid and an α-glycosyl saccharide in an amount of 0.5-fold to 30-fold higher than that of the L-ascorbic acid; applying a saccharide-transferring enzyme to the solution containing said L-ascorbic acid and said α-glycosyl saccharide at a pH in the range of 3-9, and permitting said enzyme to act on said L-ascorbic acid and saccharide to form a α-glycosyl-L-ascorbic acid exhibiting no direct reducing activity; and   recovering the α-glycosyl-L-ascorbic acid.   
     
     
       6. A cosmetic which contains as the effective ingredient an α-glycosyl-L-ascorbic acid exhibiting no direct reducing activity. 
     
     
       7. The cosmetic of claim 6, wherein said α-glycosyl-L-ascorbic acid is 2-O-α-D-glucosyl-L-ascorbic acid. 
     
     
       8. The cosmetic of claim 6, wherein said α-glycosyl-L-ascorbic acid is prepared by providing a solution which contains at least 1 w/v % L-ascorbic acid and an α-glycosyl saccharide in an amount of 0.5-fold to 30-fold higher than that of the L-ascorbic acid; applying a saccharide-transferring enzyme to the solution containing said L-ascorbic acid and said α-glycosyl saccharide at a pH in the range of 3-9, and permitting said enzyme to act on said L-ascorbic acid and saccharide to form a α-glycosyl-L-ascorbic exhibiting no direct reducing activity; and   recovering the α-glycosyl-L-ascorbic acid.